pywikibot/comms/eventstreams.py
"""
Server-Sent Events client.
This file is part of the Pywikibot framework.
This module requires sseclient to be installed::
pip install "sseclient<0.0.23,>=0.0.18"
.. versionadded:: 3.0
"""
#
# (C) Pywikibot team, 2017-2023
#
# Distributed under the terms of the MIT license.
#
from __future__ import annotations
import json
from functools import partial
from requests.packages.urllib3.exceptions import ProtocolError
from requests.packages.urllib3.util.response import httplib
from pywikibot import Site, Timestamp, config, debug, warning
from pywikibot.tools import cached
from pywikibot.tools.collections import GeneratorWrapper
try:
from sseclient import SSEClient as EventSource
except ImportError as e:
EventSource = e
class EventStreams(GeneratorWrapper):
"""Generator class for Server-Sent Events (SSE) protocol.
It provides access to arbitrary streams of data including recent changes.
Usage:
>>> stream = EventStreams(streams='recentchange')
>>> stream.register_filter(type='edit', wiki='wikidatawiki', bot=True)
>>> change = next(stream)
>>> msg = '{type} on page {title} by {user}.'.format_map(change)
>>> print(msg) # doctest: +SKIP
edit on page Q2190037 by KrBot.
>>> from pprint import pprint
>>> pprint(change, width=75) # doctest: +SKIP
{'$schema': '/mediawiki/recentchange/1.0.0',
'bot': True,
'comment': '/* wbsetreference-set:2| */ [[Property:P10585]]: 96FPN, см. '
'/ see [[Template:Autofix|autofix]] на / on [[Property '
'talk:P356]]',
'id': 1728475074,
'length': {'new': 8871, 'old': 8871},
'meta': {'domain': 'www.wikidata.org',
'dt': '2022-07-12T17:54:15Z',
'id': '2cdec62f-a2b3-49b8-9a52-85a42236fb99',
'offset': 4000957901,
'partition': 0,
'request_id': 'f7896e77-fd2b-4a95-a9e4-44c1e3ad818b',
'stream': 'mediawiki.recentchange',
'topic': 'eqiad.mediawiki.recentchange',
'uri': 'https://www.wikidata.org/wiki/Q2190037'},
'minor': False,
'namespace': 0,
'parsedcomment': '\u200e<span dir="auto"><span '
'class="autocomment">Изменена ссылка на заявление: '
'</span></span> <a href="/wiki/Property:P10585" '
'title="Property:P10585">Property:P10585</a>: 96FPN, '
'см. / see <a href="/wiki/Template:Autofix" '
'title="Template:Autofix">autofix</a> на / on <a '
'href="/wiki/Property_talk:P356" title="Property '
'talk:P356">Property talk:P356</a>',
'patrolled': True,
'revision': {'new': 1676015019, 'old': 1675697125},
'server_name': 'www.wikidata.org',
'server_script_path': '/w',
'server_url': 'https://www.wikidata.org',
'timestamp': 1657648455,
'title': 'Q2190037',
'type': 'edit',
'user': 'KrBot',
'wiki': 'wikidatawiki'}
>>> pprint(next(stream), width=75) # doctest: +ELLIPSIS
{'$schema': '/mediawiki/recentchange/1.0.0',
'bot': True,
...
'server_name': 'www.wikidata.org',
'server_script_path': '/w',
'server_url': 'https://www.wikidata.org',
...
'type': 'edit',
'user': '...',
'wiki': 'wikidatawiki'}
>>> del stream
.. versionchanged:: 7.6
subclassed from :class:`tools.collections.GeneratorWrapper`
"""
def __init__(self, **kwargs) -> None:
"""Initializer.
:keyword bool canary: if True, include canary events, see
https://w.wiki/7$2z for more info
:keyword APISite site: a project site object. Used if no url is
given
:keyword pywikibot.Timestamp or str since: a timestamp for older
events; there will likely be between 7 and 31 days of
history available but is not guaranteed. It may be given as
a pywikibot.Timestamp, an ISO 8601 string or a mediawiki
timestamp string.
:keyword Iterable[str] or str streams: event stream types.
Mandatory when no url is given. Multiple streams may be
given as a string with comma separated stream types or an
iterable of strings
:keyword int or float or tuple[int or float, int or float] timeout:
a timeout value indication how long to wait to send data
before giving up
:keyword str url: an url retrieving events from. Will be set up
to a default url using _site.family settings, stream types
and timestamp
:param kwargs: keyword arguments passed to `SSEClient` and
`requests` library
:raises ImportError: sseclient is not installed
:raises NotImplementedError: no stream types specified
.. seealso:: https://stream.wikimedia.org/?doc#streams for
available Wikimedia stream types to be passed with `streams`
parameter.
"""
if isinstance(EventSource, Exception):
raise ImportError(
'sseclient is required for EventStreams;\n'
'install it with "pip install sseclient==0.0.22"\n'
)
self.filter = {'all': [], 'any': [], 'none': []}
self._total = None
self._canary = kwargs.pop('canary', False)
try:
self._site = kwargs.pop('site')
except KeyError: # T335720
self._site = Site()
self._streams = kwargs.pop('streams', None)
if self._streams and not isinstance(self._streams, str):
self._streams = ','.join(self._streams)
self._since = kwargs.pop('since', None)
if self._since:
# assume this is a mw timestamp, convert it to a Timestamp object
if isinstance(self._since, str) and '-' not in self._since:
self._since = Timestamp.fromtimestampformat(self._since)
if isinstance(self._since, Timestamp):
self._since = self._since.isoformat()
self._url = kwargs.get('url') or self.url
kwargs.setdefault('url', self._url)
kwargs.setdefault('timeout', config.socket_timeout)
self.sse_kwargs = kwargs
def __repr__(self) -> str:
"""Return representation string."""
kwargs = self.sse_kwargs.copy()
if self._site != Site():
kwargs['site'] = self._site
if self._streams:
kwargs['streams'] = self._streams
kwargs.pop('url')
if self._since:
kwargs['since'] = self._since
if kwargs['timeout'] == config.socket_timeout:
kwargs.pop('timeout')
return '{}({})'.format(self.__class__.__name__, ', '.join(
f'{k}={v!r}' for k, v in kwargs.items()))
@property
@cached
def url(self):
"""Get the EventStream's url.
:raises NotImplementedError: no stream types specified
"""
if self._streams is None:
raise NotImplementedError('No streams specified for class {}'
.format(self.__class__.__name__))
return '{host}{path}/{streams}{since}'.format(
host=self._site.eventstreams_host(),
path=self._site.eventstreams_path(),
streams=self._streams,
since=f'?since={self._since}' if self._since else '')
def set_maximum_items(self, value: int) -> None:
"""
Set the maximum number of items to be retrieved from the stream.
If not called, most queries will continue as long as there is
more data to be retrieved from the stream.
:param value: The value of maximum number of items to be retrieved
in total to set.
"""
if value is not None:
self._total = int(value)
debug('{}: Set limit (maximum_items) to {}.'
.format(self.__class__.__name__, self._total))
def register_filter(self, *args, **kwargs):
"""Register a filter.
Filter types:
There are 3 types of filter: 'all', 'any' and 'none'.
The filter type must be given with the keyword argument 'ftype'
(see below). If no 'ftype' keyword argument is given, 'all' is
assumed as default.
You may register multiple filters for each type of filter.
The behaviour of filter type is as follows:
- **'none'**: Skip if the any filter matches. Otherwise check 'all'.
- **'all'**: Skip if not all filter matches. Otherwise check 'any':
- **'any'**: Skip if no given filter matches. Otherwise pass.
Filter functions:
Filter may be specified as external function methods given as
positional argument like::
def foo(data):
return True
register_filter(foo, ftype='any')
The data dict from event is passed to the external filter function as
a parameter and that method must handle it in a proper way and return
``True`` if the filter matches and ``False`` otherwise.
Filter keys and values:
Another method to register a filter is to pass pairs of keys and values
as keyword arguments to this method. The key must be a key of the event
data dict and the value must be any value or an iterable of values the
``data['key']`` may match or be part of it. Samples::
register_filter(server_name='de.wikipedia.org') # 1
register_filter(type=('edit', 'log')) # 2
register_filter(ftype='none', bot=True) # 3
Explanation for the result of the filter function:
1. ``return data['sever_name'] == 'de.wikipedia.org'``
2. ``return data['type'] in ('edit', 'log')``
3. ``return data['bot'] is True``
:keyword ftype: The filter type, one of 'all', 'any', 'none'.
Default value is 'all'
:type ftype: str
:param args: You may pass your own filter functions here.
Every function should be able to handle the data dict from events.
:type args: callable
:param kwargs: Any key returned by event data with an event data value
for this given key.
:type kwargs: str, list, tuple or other sequence
:raise TypeError: A given args parameter is not a callable.
"""
def _is(data, key=None, value=None):
return key in data and data[key] is value
def _eq(data, key=None, value=None):
return key in data and data[key] == value
def _in(data, key=None, value=None):
return key in data and data[key] in value
ftype = kwargs.pop('ftype', 'all') # set default ftype value
# register an external filter function
for func in args:
if callable(func):
self.filter[ftype].append(func)
else:
raise TypeError(f'{func} is not a callable')
# register pairs of keys and items as a filter function
for key, value in kwargs.items():
# append function for singletons
if isinstance(value, (bool, type(None))):
self.filter[ftype].append(partial(_is, key=key, value=value))
# append function for a single value
elif isinstance(value, (str, int)):
self.filter[ftype].append(partial(_eq, key=key, value=value))
# append function for an iterable as value
else:
self.filter[ftype].append(partial(_in, key=key, value=value))
def streamfilter(self, data: dict):
"""Filter function for eventstreams.
See the description of register_filter() how it works.
:param data: event data dict used by filter functions
"""
if not self._canary and data.get('meta', {}).get('domain') == 'canary':
return False # T266798
if any(function(data) for function in self.filter['none']):
return False
if not all(function(data) for function in self.filter['all']):
return False
if not self.filter['any']:
return True
return any(function(data) for function in self.filter['any'])
@property
def generator(self):
"""Inner generator.
.. versionchanged:: 7.6
changed from iterator method to generator property
"""
n = 0
event = None
ignore_first_empty_warning = True
while self._total is None or n < self._total:
if not hasattr(self, 'source'):
self.source = EventSource(**self.sse_kwargs)
# sseclient >= 0.0.18 is required for eventstreams (T184713)
# we don't have a version string inside but the instance
# variable 'chunk_size' was newly introduced with 0.0.18
if not hasattr(self.source, 'chunk_size'):
warning(
'You may not have the right sseclient version;\n'
'sseclient >= 0.0.18 is required for eventstreams.\n'
"Install it with 'pip install \"sseclient>=0.0.18\"'")
try:
event = next(self.source)
except (ProtocolError, OSError, httplib.IncompleteRead) as e:
warning(
f'Connection error: {e}.\nTry to re-establish connection.')
del self.source
if event is not None:
self.sse_kwargs['last_id'] = event.id
continue
if event.event == 'message':
if event.data:
try:
element = json.loads(event.data)
except ValueError as e:
warning(f'Could not load json data from\n{event}\n{e}')
else:
if self.streamfilter(element):
n += 1
yield element
elif not ignore_first_empty_warning:
warning('Empty message found.')
else:
ignore_first_empty_warning = False
elif event.event == 'error':
warning(f'Encountered error: {event.data}')
else:
warning(f'Unknown event {event.event} occurred.')
debug('{}: Stopped iterating due to exceeding item limit.'
.format(self.__class__.__name__))
del self.source
def site_rc_listener(site, total: int | None = None):
"""Yield changes received from EventStream.
:param site: the Pywikibot.Site object to yield live recent changes for
:type site: Pywikibot.BaseSite
:param total: the maximum number of changes to return
:return: pywikibot.comms.eventstream.rc_listener configured for given site
:raises ImportError: sseclient installation is required
"""
if isinstance(EventSource, Exception):
raise ImportError('sseclient is required for EventStreams;\n'
'install it with "pip install sseclient"\n')
stream = EventStreams(streams='recentchange', site=site)
stream.set_maximum_items(total)
stream.register_filter(server_name=site.hostname())
return stream